ToggleGroup .getSelectedToggle()).getId() if statement

I am having trouble with an if-Statement in Javafx, where i check the id of the selected Radiobutton, and if it matches the string, i want to set the price of something

for (int i = 0; i < 3; i++) {
    String rbFor = "rb" + i;
    if (rbFor == ((Node) tg.getSelectedToggle()).getId()) {
        preis = sizePrice[i];
    }
}

now the problem with this is, that it just doesn't work. i can set also a regular string for example rb0 and it won't do the if statement.

rb stands for RadioButton and I set their id to "rb"+i , where i is from 0-2.

tg is my ToggleGroup for these RadioButtons.

My guess is, that it's somehow connected to the node-cast, but i am unable to solve this on my own.

I also tried something like this

if (((RadioButton) scene.lookup("#rb" + i)).isSelected())

and similar casts. but that always gave me an error.

also doing something like this didn't work:

 String rbSet = ((Node) tg.getSelectedToggle()).getId();
 if (rbFor == rbSet)

Any help is appreciated.